相关论文: Constraining $\nu$-Process Production of Fluorine …
We present the first detailed and homogeneous analysis of the s-element content in Galactic carbon stars of N-type. Abundances of Sr,Y, Zr (low-mass s-elements, or ls) and of Ba, La, Nd, Sm and Ce (high-mass s-elements, hs) are derived…
Aims. A sample of early B-type stars in OB associations and the field within the solar neighbourhood is studied comprehensively. Present-day abundances for the astrophysically most interesting chemical elements are derived. Methods.…
This study uses cool dwarfs as sources with which to probe fluorine abundances via HF. This molecule is detected for the first time in young K-M dwarf members of an OB association. Fluorine, oxygen, and carbon abundances were derived from…
Using the standard infall model of Galactic chemical evolution, we explore the origin of carbon and calculate the abundance evolution of CNO elements for 8 different models of stellar nucleosynthesis yields. The results show that, in the…
We study neutrino process nucleosynthesis in massive stars using newly calculated cross sections, an expanded reaction network, and complete and self-consistent models of the progenitor star. We reevaluate the production of light isotopes…
We consider the evolution of the light elements ($Li, Be$ and $B$) incorporating the effects of their production by both neutrino process and cosmic-ray nucleosynthesis. We test the viability of the neutrino process to resolve the long…
We present the N, O, F and Na abundance and 12C/13C isotopic ratio measurements or upper limits for a sample of 10 C-rich, metal-poor giant stars, eight enhanced in s-process (CEMP-s) elements and two poor in n-capture elements (CEMP-no).…
We compute the chemical evolution of the Galactic bulge in the context of an inside-out model for the formation of the Milky Way. The model contains updated stellar yields from massive stars. The main purpose of the paper is to compare the…
Understanding the abundance pattern of metal-poor stars and the production of heavy elements through various nucleosynthesis processes offers crucial insights into the chemical evolution of the Milky Way, revealing primary sites and major…
We use observations of heavy elements in very metal-poor stars ([Fe/H] < -2.5) in order to place constraints on the viability of collapsar models as a significant source of the r-process. We combine bipolar explosion nucleosynthesis…
A new evaluation of the constraint on the number of light neutrino species (N_nu) from big bang nucleosynthesis suggests a discrepancy between the predicted light element abundances and those inferred from observations, unless the inferred…
Two types of models have been proposed to explain the linear rise of the Be and B abundances as a function of iron observed in metal poor halo stars. In both cases, this linearity indicates that freshly synthesized C and O are accelerated…
Phosphorus (P) is one of the key ingredients for life, yet its origins in galaxies remain poorly understood. In order to investigate the production of P by supernovae, we performed near-infrared (IR) [P II] and [Fe II] line mapping of 26…
There are many candidate sites of the r-process: core-collapse supernovae (including rare magnetorotational core-collapse supernovae), neutron star mergers, and neutron star/black hole mergers. The chemical enrichment of…
We measured $^{35}$Cl abundances in 52 M giants with metallicities between -0.5 $<$ [Fe/H] $<$ 0.12. Abundances and atmospheric parameters were derived using infrared spectra from CSHELL on the IRTF and from optical echelle spectra. We…
The rapid neutron capture process (r process) is believed to be responsible for about half of the production of the elements heavier than iron and contributes to abundances of some lighter nuclides as well. A universal pattern of r-process…
Knowledge of abundance ratios as functions of metallicity can lead to insights on the origin and evolution of our Galaxy and its stellar populations. We aim to trace the chemical evolution of the neutron-capture elements Sr, Zr, La, Ce, Nd,…
[Abridged] Barium stars are moderately rare, chemically peculiar objects, which are believed to be the result of the pollution of an otherwise normal star by material from an evolved companion on the asymptotic giant branch (AGB). We aim to…
We explore modifications to the current scenario for the slow neutron capture process in asymptotic giant branch (AGB) stars to account for the Pb deficiency observed in post-AGB stars of low metallicity ([Fe/H] ~ -1.2) and low initial mass…
The synthesis of nuclei in diverse cosmic scenarios is reviewed, with a summary of the basic concepts involved before a discussion of the current status in each case is made. We review the physics of the early universe, the proton to…